New Microwave Technology for the Treatment of Drill Cuttings

Abstract

The focus of this thesis was to investigate the limitations of the new microwave susceptor technology. The technology offers promising opportunities in the treatment of oil contaminated drill cuttings to meet OSPAR and oil companies on the Norwegian Continental Shelf’s standards. The concept relies on increasing process temperature to enhance oil separation by the use of highly volatile organic compounds. The organic compounds are polar, absorb microwave radiation and are not soluble in oil. Significant amount of energy is saved during the process due to the rapid heating of the susceptor, oil and high vapour pressure contribution from the oil as a result of the increased process temperature. Drill cuttings were successfully treated to discharge limits of less than 1% by weight. It is shown that enhancing parameters, such as reducing amount of water, bed depth, adequate susceptor dousing and retention time, result in better oil separation. Susceptor decomposition as a function of microwave heating and the effect of water on decomposition was investigated in this study. Selected susceptors, MEG and TEG, showed signs of decomposition, even when mixed with different proportions of water and subjected to microwave irradiation. MEG, however, showed little signs of degradation when added to drill cuttings and recycled ten times. TEG on the other hand, showed significant signs of degradation after one cycle. The tests showed that water reduced process temperature but did not prevent decomposition.